Develop Reference

Python Sockets: my recv protocol receive all the data when i debug it but not when i run it doesnt

So my project is that I need to send a jpg image from one computer to another computer in the same network. To send the data I split the data into chunks of at least 9999 bytes and then I create a length header that tells the length of the data and I attach it to the start of the massage. here is the code:
the protocol:
import os.path
LENGTH_FIELD_SIZE = 4
PORT = 8820
COMANDS_LIST = "TAKE_SCREENSHOT\nSEND_PHOTO\nDIR\nDELETE\nCOPY\nEXECUTE\nEXIT".split("\n")
def check_cmd(data):
"""
Check if the command is defined in the protocol, including all parameters
For example, DELETE c:\work\file.txt is good, but DELETE alone is not
"""
command = ""
file_location =""
splited_data = data.split(maxsplit=1)
if len(splited_data) == 2:
command, file_location = splited_data
return (command in COMANDS_LIST) and (file_location is not None)
elif len(splited_data) == 1:
command = splited_data[0]
return command in ["TAKE_SCREENSHOT","EXIT","SEND_PHOTO"]
return False
# (3)
def create_msg(data):
"""
Create a valid protocol message, with length field
"""
data_len = len(str(data))
if data_len > 9999 or data_len == 0:
print(f"data len is bigger then 9999 or is 0, data len = {data_len} ")
return False
len_field = str(data_len).zfill(4)
# (4)
print(len_field)
return True ,f"{len_field}{data}"
def get_msg(my_socket):
"""
Extract message from protocol, without the length field
If length field does not include a number, returns False, "Error"
"""
lenght_field = ""
data = ""
try:
while len(lenght_field) < 4:
lenght_field += my_socket.recv(4).decode()
except RuntimeError as exc_run:
return False, "header wasnt sent properly"
if not lenght_field.isdigit():
return False, "error, length header is not valid"
lenght_field = lenght_field.lstrip("0")
while len(data) < int(lenght_field):
data += my_socket.recv(int(lenght_field)).decode()
return True, data
now the protocol works fine when I use the same computer for both server and client and when I debug get_msg on the other computer. when I'm not, it seems that the problem is that the part that recv the header will recv something else after a few successful recv and return an error message.
here are the server parts:
import socket
import pyautogui as pyautogui
import protocol
import glob
import os.path
import shutil
import subprocess
import base64
IP = "0.0.0.0"
PORT = 8820
PHOTO_PATH = r"C:\Users\Innon\Pictures\Screenshots\screenShot.jpg"# The path + filename where the screenshot at the server should be saved
def check_client_request(cmd):
"""
Break cmd to command and parameters
Check if the command and params are good.
For example, the filename to be copied actually exists
Returns:
valid: True/False
command: The requested cmd (ex. "DIR")
params: List of the cmd params (ex. ["c:\\cyber"])
"""
# Use protocol.check_cmd first
cmd_arr = cmd.split(maxsplit=1)
command = cmd_arr[0]
file_location = None
if len(cmd_arr) == 2:
file_location = cmd_arr[1]
if file_location == None:
return protocol.check_cmd(cmd) ,command, file_location
else:
file_location = tuple(str(file_location).split())
if (os.path.exists(file_location[0])):
return protocol.check_cmd(cmd) , command , file_location
return False , command , file_location
# Then make sure the params are valid
# (6)
def handle_client_request(command,params):
"""Create the response to the client, given the command is legal and params are OK
For example, return the list of filenames in a directory
Note: in case of SEND_PHOTO, only the length of the file will be sent
Returns:
response: the requested data
"""
# (7)
response = "no server response"
if command == "DIR":
response = glob.glob(f"{params[0]}\\*.*" )
if command == "DELETE":
os.remove(params[0])
response = f"{params[0]} was deleted"
if command == "COPY":
try:
shutil.copy(params[0],params[1])
response = f"{params[0]} was copyed to {params[1]}"
except FileNotFoundError as ex1:
response = ex1
except IndexError as ex2:
response = ex2
if command == "EXECUTE":
subprocess.call(params[0])
response = f"{params[0]} was executed"
if command == "TAKE_SCREENSHOT":
#todo find a way to know and create the locatipn of screen shot to be saved
myScreenshot = pyautogui.screenshot()
myScreenshot.save(PHOTO_PATH)
response = f"screen shot have been taken and been saved at {PHOTO_PATH}"
if command == "SEND_PHOTO":
with open(PHOTO_PATH, "rb") as file:
file_data = base64.b64encode(file.read()).decode()
print(file_data)
is_vaild_response, img_length = protocol.create_msg(len(file_data))
print(img_length)
img_data = ""
if not is_vaild_response:
response = "img length data isnt valid"
return response
while len(file_data) > 0:
chunk_data = file_data[:9999]
is_vaild_response, data = protocol.create_msg(chunk_data)
if not is_vaild_response:
response = "img data isnt valid"
return response
img_data += data
file_data = file_data[9999:]
response = f"{img_length}{img_data}"
return response
def main():
# open socket with client
server_socket = socket.socket()
server_socket.bind((IP,PORT))
server_socket.listen(1)
# (1)
client_socket, addr = server_socket.accept()
# handle requests until user asks to exit
while True:
# Check if protocol is OK, e.g. length field OK
valid_protocol, cmd = protocol.get_msg(client_socket)
print(f"got message {valid_protocol}")
if valid_protocol:
# Check if params are good, e.g. correct number of params, file name exists
valid_cmd, command, params = check_client_request(cmd)
print(f"check_client_request {valid_cmd}")
if valid_cmd:
# (6)
if command == 'EXIT':
break
if command == 'SEND_PHOTO':
data = handle_client_request(command, params)
client_socket.sendall(data.encode())
continue
# prepare a response using "handle_client_request"
data = handle_client_request(command,params)
# add length field using "create_msg"
is_vaild_response , response = protocol.create_msg(data)
print(f"creat_msg {is_vaild_response}")
# send to client
if is_vaild_response:
client_socket.sendall(response.encode())
else:
# prepare proper error to client
resp = 'Bad command or parameters'
is_vaild_response , response = protocol.create_msg(resp)
# send to client
client_socket.sendall(response.encode())
else:
# prepare proper error to client
resp = 'Packet not according to protocol'
is_vaild_response, response = protocol.create_msg(resp)
#send to client
client_socket.sendall(response.encode())
# Attempt to clean garbage from socket
client_socket.recv(1024)
# close sockets
resp = "Closing connection"
print(resp)
is_vaild_response, response = protocol.create_msg(resp)
client_socket.sendall(response.encode())
client_socket.close()
server_socket.close()
if __name__ == '__main__':
main()
and the client:
import socket
import base64
import protocol
IP = "127.0.0.1"
SAVED_PHOTO_LOCATION = r'C:\Users\Innon\Pictures\Saved Pictures\screenShot.jpg' # The path + filename where the copy of the screenshot at the client should be saved
def handle_server_response(my_socket, cmd):
"""
Receive the response from the server and handle it, according to the request
For example, DIR should result in printing the contents to the screen,
Note- special attention should be given to SEND_PHOTO as it requires and extra receive
"""
# (8) treat all responses except SEND_PHOTO
if "SEND_PHOTO" not in cmd:
vaild_data, data = protocol.get_msg(my_socket)
if vaild_data:
return data
# (10) treat SEND_PHOTO
else:
pic_data = ""
vaild_pick_len, pic_len = protocol.get_msg(my_socket)
if pic_len.isdigit() == False:
print(f"picture length is not valid. got massage: {pic_len}")
return
with open(SAVED_PHOTO_LOCATION, "wb") as file:
while len(pic_data) < int(pic_len):
vaild_data, data = protocol.get_msg(my_socket)
if not vaild_data:
return f"img data isnt valid. {data}"
pic_data += data
print(pic_data)
file.write(base64.b64decode(pic_data.encode()))
return "img was recived succesfully "
def main():
# open socket with the server
my_socket = socket.socket()
my_socket.connect((IP,8820))
# (2)
# print instructions
print('Welcome to remote computer application. Available commands are:\n')
print('TAKE_SCREENSHOT\nSEND_PHOTO\nDIR\nDELETE\nCOPY\nEXECUTE\nEXIT')
# loop until user requested to exit
while True:
cmd = input("Please enter command:\n")
if protocol.check_cmd(cmd):
valid_pack , packet = protocol.create_msg(cmd)
if valid_pack:
my_socket.sendall(packet.encode())
print(handle_server_response(my_socket, cmd))
if cmd == 'EXIT':
break
else:
print("Not a valid command, or missing parameters\n")
my_socket.close()
if __name__ == '__main__':
main()
here is how the problem looks like:thi is how it looks
here is how to needs look like:
the right way
thank you.

the solution was to change get_msg function in the protocol:
while len(data) < int(lenght_field):
data += my_socket.recv(int(lenght_field) - len(data)).decode()
instead of:
while len(data) < int(lenght_field):
data += my_socket.recv(int(lenght_field)).decode()

Opening 2 serial ports simultaneously in python (one tx one for rx)

I am making a throughput test for a bluetooth link, and I need to send data through a serial port to one bluetooth device which will then transport that data wirelessly to another bluetooth device. The other device will then complete the circuit by sending the data back to the host PC via a different serial port.
The problem seems to be when I attempt to open up 2 different instances of PySerial, the program simply hangs. I have isolated it down to running vs. hanging when I comment out one of the two serial port instantiations. Anyone see a problem with how I'm doing this? If so, what is the proper way to do this? See code below:
#/usr/bin/python
import serial
import time
import sys
DEFAULT_BAUD = 115200
SEND_SIZE = 100
def addPath(file):
pth, fl = os.path.split(__file__)
return os.path.join(pth, file)
def is_number(s):
try:
int(s, 16)
return True
except:
return False
class SerialReader():
def __init__(self, portRx, portTx):
self.portTx = portTx
self.portRx = portRx
self.start_time__sec = time.time()
self.interval__sec = 0
self.buffer = []
self.sendtext = ''.join([str(i) for i in range(SEND_SIZE)])
# send first batch of data
self.portTx.write(self.sendtext)
def didDataArrive(self):
# Read port
self.buffer.extend(list(self.portRx.read(1024)))
# Step through the buffer byte and byte and see if the tick text
# is at the front.
while len(self.buffer) >= len(self.sendtext):
if self.buffer[:len(self.sendtext)] == self.sendtext:
# Discard the tick text
self.buffer = self.buffer[len(self.sendtext):]
# Record time
snapshot__sec = time.time()
self.interval__sec = snapshot__sec - self.start_time__sec
self.start_time__sec = snapshot__sec
# send more data
self.portTx.write(self.sendtext)
return True
else:
self.buffer.pop(0)
return False
def main(port1, port2, baudrate1 = DEFAULT_BAUD, baudrate2 = DEFAULT_BAUD):
try:
import serial
except:
traceback.print_exc()
print "="*60
print "You need to install PySerial"
print "Windows: easy_install pyserial"
print "Mac/Linux: sudo easy_install pyserial"
try:
s1 = serial.Serial(port1, baudrate1, timeout = 0.1)
s2 = serial.Serial(port2, baudrate2, timeout = 0.1)
print "Loading serial ports"
except:
print "Serial port error"
exit()
plot_stop = False
dataread = SerialReader(s2, s1)
try:
while plot_stop == False:
if dataread.didDataArrive():
print dataread.interval__sec
except KeyboardInterrupt:
print "Keyboard Interrupt"
plot_stop = True
finally:
print "Closing"
s1.close()
s2.close()
if __name__ == '__main__':
if (len(sys.argv) < 3):
print "Usage: python extract_data.py phonelink_serialport phonelinkclient_serialport [baudrate1] [baudrate2]"
else:
main(*sys.argv[1:])
If I remove one of the following lines (doesn't matter which one), the python script runs (although it eventually crashes because in the code it eventually tries to reference both ports). If I leave these lines in, the program seems to just hang (it just seems to sit there and run indefinitely):
s1 = serial.Serial(port1, baudrate1, timeout = 0.1)
s2 = serial.Serial(port2, baudrate2, timeout = 0.1)

Python Server - Processing WebSocket.close()

I'm working on a small server from the code provided below. The server will interact with a websocket to take a message from a websocket, send a message back to the websocket, and once the websocket calls .close() the server will "shutdown" or close the connection.
However at the moment, when the websocket calls .close() the time it takes to disconnect is long. ( I'm assuming it's the 300 second time out for websockets that occurs when ping/pong messages aren't sent to keep the connection alive). In turn, I think this means that the connection is not closing completely and is just getting lost.
Is there a way to determine and fix this?
I've been reading up on the python socket server documentation and other various sources to figure it out and have come up short. My only solution is the hack comment in the code below.
https://docs.python.org/2/library/socketserver.html
http://pymotw.com/2/SocketServer/
import struct
import SocketServer
from base64 import b64encode
from hashlib import sha1
from mimetools import Message
from StringIO import StringIO
class WebSocketsHandler(SocketServer.StreamRequestHandler):
magic = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
def setup(self):
SocketServer.StreamRequestHandler.setup(self)
print "connection established", self.client_address
self.handshake_done = False
def handle(self):
while True:
if not self.handshake_done:
self.handshake()
else:
self.read_next_message()
def read_next_message(self):
length = ord(self.rfile.read(2)[1]) & 127
if length == 126:
length = struct.unpack(">H", self.rfile.read(2))[0]
elif length == 127:
length = struct.unpack(">Q", self.rfile.read(8))[0]
masks = [ord(byte) for byte in self.rfile.read(4)]
decoded = ""
for char in self.rfile.read(length):
decoded += chr(ord(char) ^ masks[len(decoded) % 4])
self.on_message(decoded)
def send_message(self, message):
self.request.send(chr(129))
length = len(message)
if length <= 125:
self.request.send(chr(length))
elif length >= 126 and length <= 65535:
self.request.send(chr(126))
self.request.send(struct.pack(">H", length))
else:
self.request.send(chr(127))
self.request.send(struct.pack(">Q", length))
self.request.send(message)
def handshake(self):
data = self.request.recv(1024).strip()
headers = Message(StringIO(data.split('\r\n', 1)[1]))
if headers.get("Upgrade", None) != "websocket":
return
print 'Handshaking...'
key = headers['Sec-WebSocket-Key']
digest = b64encode(sha1(key + self.magic).hexdigest().decode('hex'))
response = 'HTTP/1.1 101 Switching Protocols\r\n'
response += 'Upgrade: websocket\r\n'
response += 'Connection: Upgrade\r\n'
response += 'Sec-WebSocket-Accept: %s\r\n\r\n' % digest
self.handshake_done = self.request.send(response)
def on_message(self, message):
print message
self.send_message("How do you do?")
if __name__ == "__main__":
server = SocketServer.TCPServer(
("", 9999), WebSocketsHandler)
server.serve_forever()
[Slightly] modified from: https://gist.github.com/jkp/3136208
NOTE: I am aware of the server.serve_forever() and how that may be an issue. I'm looking for a suggestion or direction along the lines of :
def on_close(): ...

I think you need to implement an onClose() method on your server side. Why you do not use some python framework that has websocket support such as Tornado or Authobahn.
Here is an example for websocket server in python using Tornado
https://developer.mbed.org/cookbook/Websockets-Server
I hope this will help you.

WebSocket server in Python: 'module' object has no attribute 'AF_INET' [duplicate]

This question already has answers here:
Importing installed package from script with the same name raises "AttributeError: module has no attribute" or an ImportError or NameError
(2 answers)
Closed 7 months ago.
I am trying to run this simple Python WebSocket, with a couple very minor changes. I am running Python 2.4.3 because I cannot use an newer version, but I'm not sure how much that matters.
Here is the error I'm getting:
Traceback (most recent call last):
File "socket.py", line 258, in ?
server = WebSocketServer("localhost", 8000, WebSocket)
File "socket.py", line 205, in __init__
self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
AttributeError: 'module' object has no attribute 'AF_INET'
And here is my code:
import time
import struct
import socket
import base64
import sys
from select import select
import re
import logging
from threading import Thread
import signal
# Simple WebSocket server implementation. Handshakes with the client then echos back everything
# that is received. Has no dependencies (doesn't require Twisted etc) and works with the RFC6455
# version of WebSockets. Tested with FireFox 16, though should work with the latest versions of
# IE, Chrome etc.
#
# rich20b#gmail.com
# Adapted from https://gist.github.com/512987 with various functions stolen from other sites, see
# below for full details.
# Constants
MAGICGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
TEXT = 0x01
BINARY = 0x02
# WebSocket implementation
class WebSocket(object):
handshake = (
"HTTP/1.1 101 Web Socket Protocol Handshake\r\n"
"Upgrade: WebSocket\r\n"
"Connection: Upgrade\r\n"
"Sec-WebSocket-Accept: %(acceptstring)s\r\n"
"Server: TestTest\r\n"
"Access-Control-Allow-Origin: http://localhost\r\n"
"Access-Control-Allow-Credentials: true\r\n"
"\r\n"
)
# Constructor
def __init__(self, client, server):
self.client = client
self.server = server
self.handshaken = False
self.header = ""
self.data = ""
# Serve this client
def feed(self, data):
# If we haven't handshaken yet
if not self.handshaken:
logging.debug("No handshake yet")
self.header += data
if self.header.find('\r\n\r\n') != -1:
parts = self.header.split('\r\n\r\n', 1)
self.header = parts[0]
if self.dohandshake(self.header, parts[1]):
logging.info("Handshake successful")
self.handshaken = True
# We have handshaken
else:
logging.debug("Handshake is complete")
# Decode the data that we received according to section 5 of RFC6455
recv = self.decodeCharArray(data)
# Send our reply
self.sendMessage(''.join(recv).strip());
# Stolen from http://www.cs.rpi.edu/~goldsd/docs/spring2012-csci4220/websocket-py.txt
def sendMessage(self, s):
"""
Encode and send a WebSocket message
"""
# Empty message to start with
message = ""
# always send an entire message as one frame (fin)
b1 = 0x80
# in Python 2, strs are bytes and unicodes are strings
if type(s) == unicode:
b1 |= TEXT
payload = s.encode("UTF8")
elif type(s) == str:
b1 |= TEXT
payload = s
# Append 'FIN' flag to the message
message += chr(b1)
# never mask frames from the server to the client
b2 = 0
# How long is our payload?
length = len(payload)
if length < 126:
b2 |= length
message += chr(b2)
elif length < (2 ** 16) - 1:
b2 |= 126
message += chr(b2)
l = struct.pack(">H", length)
message += l
else:
l = struct.pack(">Q", length)
b2 |= 127
message += chr(b2)
message += l
# Append payload to message
message += payload
# Send to the client
self.client.send(str(message))
# Stolen from http://stackoverflow.com/questions/8125507/how-can-i-send-and-receive-websocket-messages-on-the-server-side
def decodeCharArray(self, stringStreamIn):
# Turn string values into opererable numeric byte values
byteArray = [ord(character) for character in stringStreamIn]
datalength = byteArray[1] & 127
indexFirstMask = 2
if datalength == 126:
indexFirstMask = 4
elif datalength == 127:
indexFirstMask = 10
# Extract masks
masks = [m for m in byteArray[indexFirstMask : indexFirstMask+4]]
indexFirstDataByte = indexFirstMask + 4
# List of decoded characters
decodedChars = []
i = indexFirstDataByte
j = 0
# Loop through each byte that was received
while i < len(byteArray):
# Unmask this byte and add to the decoded buffer
decodedChars.append( chr(byteArray[i] ^ masks[j % 4]) )
i += 1
j += 1
# Return the decoded string
return decodedChars
# Handshake with this client
def dohandshake(self, header, key=None):
logging.debug("Begin handshake: %s" % header)
# Get the handshake template
handshake = self.handshake
# Step through each header
for line in header.split('\r\n')[1:]:
name, value = line.split(': ', 1)
# If this is the key
if name.lower() == "sec-websocket-key":
# Append the standard GUID and get digest
combined = value + MAGICGUID
response = base64.b64encode(combined.digest())
# Replace the placeholder in the handshake response
handshake = handshake % { 'acceptstring' : response }
logging.debug("Sending handshake %s" % handshake)
self.client.send(handshake)
return True
def onmessage(self, data):
#logging.info("Got message: %s" % data)
self.send(data)
def send(self, data):
logging.info("Sent message: %s" % data)
self.client.send("\x00%s\xff" % data)
def close(self):
self.client.close()
# WebSocket server implementation
class WebSocketServer(object):
# Constructor
def __init__(self, bind, port, cls):
self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.socket.bind((bind, port))
self.bind = bind
self.port = port
self.cls = cls
self.connections = {}
self.listeners = [self.socket]
# Listen for requests
def listen(self, backlog=5):
self.socket.listen(backlog)
logging.info("Listening on %s" % self.port)
# Keep serving requests
self.running = True
while self.running:
# Find clients that need servicing
rList, wList, xList = select(self.listeners, [], self.listeners, 1)
for ready in rList:
if ready == self.socket:
logging.debug("New client connection")
client, address = self.socket.accept()
fileno = client.fileno()
self.listeners.append(fileno)
self.connections[fileno] = self.cls(client, self)
else:
logging.debug("Client ready for reading %s" % ready)
client = self.connections[ready].client
data = client.recv(4096)
fileno = client.fileno()
if data:
self.connections[fileno].feed(data)
else:
logging.debug("Closing client %s" % ready)
self.connections[fileno].close()
del self.connections[fileno]
self.listeners.remove(ready)
# Step though and delete broken connections
for failed in xList:
if failed == self.socket:
logging.error("Socket broke")
for fileno, conn in self.connections:
conn.close()
self.running = False
# Entry point
if __name__ == "__main__":
logging.basicConfig(level=logging.DEBUG, format="%(asctime)s - %(levelname)s - %(message)s")
server = WebSocketServer("localhost", 8000, WebSocket)
server_thread = Thread(target=server.listen, args=[5])
server_thread.start()
# Add SIGINT handler for killing the threads
def signal_handler(signal, frame):
logging.info("Caught Ctrl+C, shutting down...")
server.running = False
sys.exit()
signal.signal(signal.SIGINT, signal_handler)
while True:
time.sleep(100)

It appears that you've named your own file socket.py, so when you import socket, you're not getting the system library (it's just re-importing the file you're currently in - which has no AF_INET symbol). Try renaming your file something like mysocket.py.

Even after changing the file name, if you are running the python from the terminal.
(you may get the same error)
Kindly
rm -rf socket.pyc
(previously compiled bytecode)

I had the same problem, I was literally stuck here for hours, tried re installing it a million times, but found the solution.
1) Make sure the file name is not socket.py,
2) Change the directory, it will not work in the home directory due to some permission issues.
If you have by anychance saved the file as socket.py, do not copy the same file or rename it to something else, the problem will persist.
What I advice you to do is, open a new folder in a different directory, write a simple socket code which involved AF_INET. Try to run it. It should work.

Issue can be that you have a file or Cache name socket.py or socket.pyc
rm -rf socket.py
rm -rf socket.pyc
Hopefully this will resolve your import issue. Gud Luck

enter the current working directory
and remove the files named 'socket.py' and 'socket.pyc'

How can I check the data transfer on a network interface in python?

There is a socket method for getting the IP of a given network interface:
import socket
import fcntl
import struct
def get_ip_address(ifname):
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
return socket.inet_ntoa(fcntl.ioctl(
s.fileno(),
0x8915, # SIOCGIFADDR
struct.pack('256s', ifname[:15])
)[20:24])
Which returns the following:
>>> get_ip_address('lo')
'127.0.0.1'
>>> get_ip_address('eth0')
'38.113.228.130'
Is there a similar method to return the network transfer of that interface? I know I can read /proc/net/dev but I'd love a socket method.

The best way to poll ethernet interface statistics is through SNMP...
It looks like you're using linux... if so, load up your snmpd with these options... after installing snmpd, in your /etc/defaults/snmpd (make sure the line with SNMPDOPTS looks like this):
SNMPDOPTS='-Lsd -Lf /dev/null -u snmp -I -smux,usmConf,iquery,dlmod,diskio,lmSensors,hr_network,snmpEngine,system_mib,at,interface,ifTable,ipAddressTable,ifXTable,ip,cpu,tcpTable,udpTable,ipSystemStatsTable,ip,snmp_mib,tcp,icmp,udp,proc,memory,snmpNotifyTable,inetNetToMediaTable,ipSystemStatsTable,disk -Lsd -p /var/run/snmpd.pid'
You might also need to change the ro community to public See Note 1 and set your listening interfaces in /etc/snmp/snmpd.conf (if not on the loopback)...
Assuming you have a functional snmpd, at this point, you can poll ifHCInBytes and ifHCOutBytes See Note 2 for your interface(s) in question using this...
poll_bytes.py:
from SNMP import v2Manager
import time
def poll_eth0(manager=None):
# NOTE: 2nd arg to get_index should be a valid ifName value
in_bytes = manager.get_index('ifHCInOctets', 'eth0')
out_bytes = manager.get_index('ifHCOutOctets', 'eth0')
return (time.time(), int(in_bytes), int(out_bytes))
# Prep an SNMP manager object...
mgr = v2Manager('localhost')
mgr.index('ifName')
stats = list()
# Insert condition below, instead of True...
while True:
stats.append(poll_eth0(mgr))
print poll_eth0(mgr)
time.sleep(5)
SNMP.py:
from subprocess import Popen, PIPE
import re
class v2Manager(object):
def __init__(self, addr='127.0.0.1', community='public'):
self.addr = addr
self.community = community
self._index = dict()
def bulkwalk(self, oid='ifName'):
cmd = 'snmpbulkwalk -v 2c -Osq -c %s %s %s' % (self.community,
self.addr, oid)
po = Popen(cmd, shell=True, stdout=PIPE, executable='/bin/bash')
output = po.communicate()[0]
result = dict()
for line in re.split(r'\r*\n', output):
if line.strip()=="":
continue
idx, value = re.split(r'\s+', line, 1)
idx = idx.replace(oid+".", '')
result[idx] = value
return result
def bulkwalk_index(self, oid='ifOutOctets'):
result = dict()
if not (self._index==dict()):
vals = self.bulkwalk(oid=oid)
for key, val in vals.items():
idx = self._index.get(key, None)
if not (idx is None):
result[idx] = val
else:
raise ValueError, "Could not find '%s' in the index (%s)" % self.index
else:
raise ValueError, "Call the index() method before calling bulkwalk_index()"
return result
def get_index(self, oid='ifOutOctets', index=''):
# This method is horribly inefficient... improvement left as exercise for the reader...
if index:
return self.bulkwalk_index().get(index, "<unknown>")
else:
raise ValueError, "Please include an index to get"
def index(self, oid='ifName'):
self._index = self.bulkwalk(oid=oid)
END NOTES:
SNMP v2c uses clear-text authentication. If you are worried about security / someone sniffing your traffic, change your community and restrict queries to your linux machine by source ip address. The perfect world would be to modify the SNMP.py above to use SNMPv3 (which encrypts sensitive data); most people just use a non-public community and restrict snmp queries by source IP.
ifHCInOctets and ifHCOutOctets provide instantaneous values for the number of bytes transferred through the interface. If you are looking for data transfer rate, of course there will be some additional math involved.